The present invention is directed to fasteners, and more particularly, to fasteners having a generally U-shaped, staple-like construction, to driving elements and fastener placement systems therefor, to sticks of the fasteners, to methods of fastening and to fastened workpieces.
A wide variety of forcibly driven fasteners have been employed in the past for the fastening together of two or more workpieces. Such fasteners have included everything from ordinary construction nails to U-shaped, staple-like fasteners. In some instances in the past a plurality of the fasteners are formed into a stick which can be inserted into a tool for positioning and driving the fasteners into the workpieces which are to be fastened together. During the fastening procedure, the sharp leading ends of the spaced legs of the staple-like fasteners are positioned over at least one of the workpieces to be fastened, and a driving element in the tool is forcibly driven against the crown which joins the legs of one of the staple-like fasteners to separate the leading fastener from a stick of the fasteners, and forcibly drive it into the workpiece or workpieces.
Nails have also been employed in the past in which the nails are adhesively and sequentially attached to each other to form a stick of the nails, the stick is inserted into the magazine of a fastener driving tool in a manner similar to the aforementioned staples, and a driving element of the driving tool contacts and forcibly drives the lead nail in the stick into the workpieces being fastened together.
Although in many of the prior fasteners and fastener systems a force is applied when the fastener is in the process of being forcibly driven into the workpieces which are being fastened, once driving of the fastener has been completed, any forces of substantial magnitude which may have existed during the driving step and which might have tended to urge two workpieces together generally cease. Moreover, neither the configuration of the prior fasteners nor the manner in which they are driven to achieve the fastening function have been generally conducive to exerting any substantial. continuing force which tends to urge the two workpieces together once the fasteners are in place. It would be desirable if a continuing force could be exerted after the driving of a fastener has ceased and which force would tend to urge the two workpieces together in their fastened condition. The existence of such continuing force would among other things firmly hold the workpieces together after fastening and during handling and use of the fastened workpieces. This would substantially reduce any tendency or possibility of relative movement between the two workpieces after they have been fastened together and the possible misalignment or separation of the workpieces due to such movement.
It has been discovered in the present invention that continuing forces advantageously may be simply, easily and readily achieved which tend to urge and hold at least two workpieces together both during the forcible driving of the fastener or fasteners, as well as after the fastener has been forcibly driven and placed in the workpieces. In the present invention these desired continuing forces are achieved by utilizing a U-shaped, staple-like fastener having a pair of legs which are spaced from each other by a crown which transversely extends between the upper ends of the legs to connect the legs to each other adjacent their upper ends, but space the upper ends apart by a given distance. During or at the completion of the driving of the fastener into the workpieces, action is taken on or by the fastener which tends to or attempts to shorten the distance between the upper ends of the legs. This results in the generation and exertion of forces which act to continue to urge the two workpieces together after the placement of the fastener as will be described in further detail to follow. Another advantage of the present invention is that these continuing forces may be easily and readily accomplished utilizing generally previously known and available fasteners, and the desired continuing forces may be accomplished without the need to employ complex or expensive specially constructed tools or procedures.
In one principal aspect of the present invention, an improved driving element, fastener placement system, method of fastening and combination of fastened workpieces comprises a generally U-shaped, staple-like fastener having a pair of legs spaced from each other by a crown which transversely extends between the upper ends of the legs to connect the legs to each other adjacent their upper ends and space the upper ends of the legs apart by a given distance. Each of the legs also has an opposite lower end which is adapted to enter the respective workpieces which are to be fastened together. The fastener is positioned with the lower end of one leg in contact with one of the workpieces and the lower end of the other leg in contact with the other workpiece, and the fastener is then forcibly driven into the respective workpieces by a driving element which acts upon the crown in a manner to attempt or tend to shorten the distance between the upper end of at least one of the legs and the other leg. This will create continuing forces which tend to continue to urge the respective workpieces together after the fastener has been driven.
In another principal aspect of the present invention, the attempt to shorten the distance is produced by bending the fastener crown.
In still another principal aspect of the present invention, the crown is bent adjacent the upper end of at least one of the legs to urge the upper end of that leg toward the other leg.
In still another principal aspect of the present invention, the crown is bent intermediate the upper ends of both of the legs to urge the upper ends of the legs toward each other.
In still another principal aspect of the present invention, the bending of the crown is achieved by at least one projection extending from an edge of the driving element of a powered driving head toward and into contact with the fastener crown, and the projection forcibly drives the crown into the workpieces while at the same time tending to bend the crown.
In still another principal aspect of the present invention, the bent portions of the crown are countersunk into the workpieces.
In still another principal aspect of the present invention, prior to being driven into the workpieces the legs of the fastener are closer to each other adjacent the ends at which they are attached to the crown than at the opposite ends to produce, at least in part, the continuing forces which tend to continue to urge the respective workpieces together after the fastener has been driven.
In still another principal aspect of the present invention, a stick is formed of a plurality of generally U-shaped fasteners which are arranged in serial adjacent relationship to each other and along a longitudinal axis. Each of the fasteners comprises a pair of elongate legs spaced from each other and depending at one end from, attached to and extending at a substantial angle from the opposite ends of a crown which extends transversely between the ends of the legs of each of the fasteners. Both of the legs and the crown of each fastener are located in a plane, the planes of adjacent fasteners are substantially parallel to each other, and the longitudinal axis extends at an acute angle to the planes of the fasteners.
In still another principal aspect of the present invention, the two workpieces fastened together are wood construction pieces.
In still another principal aspect of the present invention, the two workpieces may each include planar faces in which the planes of the respective faces are either parallel to each other, coplanar to each other, or extend at a substantial angle to each other, and the legs of the fastener may be inserted through each of the respective planes with the crown of the fastener extending between the respective planes to fasten the two workpieces together.
These and other objects, features and advantages of the present invention will be more clearly understood through a consideration of the following detailed description.